U.S. patent application number 10/816125 was filed with the patent office on 2004-09-23 for snowmobile four-cycle engine arrangement.
This patent application is currently assigned to Suzuki Motor Corporation. Invention is credited to Matsumura, Hitoshi, Yatagai, Yasuaki.
Application Number | 20040182621 10/816125 |
Document ID | / |
Family ID | 26599368 |
Filed Date | 2004-09-23 |
United States Patent
Application |
20040182621 |
Kind Code |
A1 |
Yatagai, Yasuaki ; et
al. |
September 23, 2004 |
Snowmobile four-cycle engine arrangement
Abstract
A snowmobile four-cycle engine arrangement, includes: a
four-cycle engine arranged in an engine compartment formed in the
front body of a snowmobile with its crankshaft laid substantially
parallel to the body width and having a cylinder case inclined
forwards with respect to the vehicle's direction of travel. The
engine employs a dry sump oil supplying system and an oil tank
separate from the engine is provided. Another snowmobile four-cycle
engine arrangement includes: a four-cycle engine having a cylinder
head at its top, arranged in the engine compartment and inclined
forwards with respect to the vehicle's direction of travel with an
intake path provided on the upper portion of the engine body. An
intercooler for cooling the intake air is arranged in a tunnel
created inside the body frame for accommodating a track belt.
Inventors: |
Yatagai, Yasuaki;
(Hamamatsu-shi, JP) ; Matsumura, Hitoshi;
(Hamamatsu-shi, JP) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
1100 N GLEBE ROAD
8TH FLOOR
ARLINGTON
VA
22201-4714
US
|
Assignee: |
Suzuki Motor Corporation
Shizoka-ken
JP
|
Family ID: |
26599368 |
Appl. No.: |
10/816125 |
Filed: |
April 2, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10816125 |
Apr 2, 2004 |
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10365417 |
Feb 13, 2003 |
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10365417 |
Feb 13, 2003 |
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09925522 |
Aug 10, 2001 |
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6561297 |
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Current U.S.
Class: |
180/182 |
Current CPC
Class: |
B62M 27/02 20130101;
B62M 2027/023 20130101; B62M 2027/026 20130101; F02B 2075/027
20130101 |
Class at
Publication: |
180/182 |
International
Class: |
B62M 027/02; B62M
029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 6, 2000 |
JP |
2000-270363 |
Sep 20, 2000 |
JP |
2000-285417 |
Claims
What is claimed is:
1. A snowmobile four-cycle engine arrangement, comprising: a
four-cycle engine arranged in an engine compartment formed in the
front body of a snowmobile with its crankshaft laid substantially
parallel to the body width and having a cylinder portion inclined
forwards with respect to the vehicle's direction of travel, the
engine employing a dry sump oil supplying system; and an oil tank
provided in the engine compartment, separately from the engine.
2. The snowmobile four-cycle engine arrangement according to claim
1, wherein the oil tank is arranged in front of the engine and on
the top of a front suspension housing which is projected upwards
from the bottom of the engine compartment.
3. The snowmobile four-cycle engine arrangement according to claim
1, wherein the oil tank is arranged in the rear of the engine and
on the upper face of a track housing which is projected upwards
from the bottom of the engine compartment.
4. The snowmobile four-cycle engine arrangement according to claim
2, wherein the oil tank is arranged in the rear of the engine and
on the upper face of a track housing which is projected upwards
from the bottom of the engine compartment.
5. The snowmobile four-cycle engine arrangement according to claim
1, wherein the engine compartment has an opening port with a mating
openable and closable lid element, at its bottom for creating
communication between the inside of the engine compartment and the
external space, at a position opposing the bottom of the oil pan of
the engine.
6. The snowmobile four-cycle engine arrangement according to claim
2, wherein the engine compartment has an opening port with a mating
openable and closable lid element, at its bottom for creating
communication between the inside of the engine compartment and the
external space, at a position opposing the bottom of the oil pan of
the engine.
7. The snowmobile four-cycle engine arrangement according to claim
3, wherein the engine compartment has an opening port with a mating
openable and closable lid element, at its bottom for creating
communication between the inside of the engine compartment and the
external space, at a position opposing the bottom of the oil pan of
the engine.
8. The snowmobile four-cycle engine arrangement according to claim
4, wherein the engine compartment has an opening port with a mating
openable and closable lid element, at its bottom for creating
communication between the inside of the engine compartment and the
external space, at a position opposing the bottom of the oil pan of
the engine.
9. A snowmobile four-cycle engine arrangement, comprising: a
four-cycle engine having a cylinder head on the top thereof and
arranged in an engine compartment formed in the front body of a
snowmobile with its crankshaft laid substantially parallel to the
body width and its engine body inclined forwards with respect to
the vehicle's direction of travel; and an intake path on the upper
face of the engine body, characterized in that a heat exchanger for
cooling the engine cooling water, engine oil or air to be supplied
to the engine is arranged in the tunnel created inside the body
frame for accommodating a track for driving.
10. The snowmobile four-cycle engine arrangement according to claim
9, wherein the heat exchanger is disposed in front of the track,
with respect to the vehicle's direction of travel, inside the
tunnel.
11. The snowmobile four-cycle engine arrangement according to claim
9, wherein an intercooler for cooling the air to be supplied to the
engine is put into use as the heat exchanger.
12. The snowmobile four-cycle engine arrangement according to claim
10, wherein an intercooler for cooling the air to be supplied to
the engine is put into use as the heat exchanger.
13. The snowmobile four-cycle engine arrangement according to claim
9, wherein an oil cooler for cooling the engine oil is put into use
as the heat exchanger.
14. The snowmobile four-cycle engine arrangement according to claim
10, wherein an oil cooler for cooling the engine oil is put into
use as the heat exchanger.
15. The snowmobile four-cycle engine arrangement according to claim
9, wherein a radiator for cooling the engine cooling water is put
into use as the heat exchanger.
16. The snowmobile four-cycle engine arrangement according to claim
10, wherein a radiator for cooling the engine cooling water is put
into use as the heat exchanger.
17. The snowmobile four-cycle engine arrangement according to claim
9, wherein an integrated configuration comprised of an oil cooler
for cooling the engine oil and a radiator for cooling the engine
cooling water is put into use as the heat exchanger.
18. The snowmobile four-cycle engine arrangement according to claim
10, wherein an integrated configuration comprised of an oil cooler
for cooling the engine oil and a radiator for cooling the engine
cooling water is put into use as the heat exchanger.
19. The snowmobile four-cycle engine arrangement according to claim
13, wherein a thermostat is interposed in the oil path of the oil
cooler.
20. The snowmobile four-cycle engine arrangement according to claim
14, wherein a thermostat is interposed in the oil path of the oil
cooler.
21. The snowmobile four-cycle engine arrangement according to claim
17, wherein a thermostat is interposed in the oil path of the oil
cooler.
22. The snowmobile four-cycle engine arrangement according to claim
18, wherein a thermostat is interposed in the oil path of the oil
cooler.
Description
BACKGROUND OF THE INVENTION
[0001] (1) Field of the Invention
[0002] The present invention relates to an engine arrangement, and
in particular relates to an arrangement of a four-cycle engine
mounted on a snowmobile.
[0003] (2) Description of the Prior Art
[0004] Conventionally, small snow vehicles such as snowmobiles have
mainly used two-cycle engines. A two-cycle engine is characterized
by a relatively simple engine configuration having the advantages
of being lightweight and compact and still providing high power.
However, two-cycle engines have drawbacks, when compared with
four-cycle engines, of emitting a greater amount of exhaust and
louder noise with greater vibrations.
[0005] The recent worldwide trend demands a silent, clean and
environment-conscious engine. Snow vehicle engines are no exception
and clean and silent engines have been desired. To fulfil this
demand, development of engines for snowmobile into a four-cycle
configuration has been studied.
[0006] As shown in FIG. 1, a typical conventional snowmobile 200
has a body frame 210 in a monocoque frame configuration, wherein an
engine 202 is mounted in a space formed between a track housing
211c and a front suspension housing 211b in the front frame (engine
mounting frame) 211. For a two-cycle engine, engine 202 is mounted
upright in an engine compartment 206.
[0007] If a four-cycle engine is attempted to be put into use for a
snowmobile in the same manner as above, the upright mounting has
been difficult because a four-cycle engine has a greater full
height compared to a two cycle engine due to its bulky cylinder
head and the necessity of an oil pan. Further, since a four-cycle
engine needs additional parts unique to it such as an alternator,
supercharger, intercooler, oil filter and the like, it has been
very difficult to lay out all these parts in a limited engine
compartment space.
[0008] To overcome the above space difficulty, there has been a
layout proposal as shown in FIG. 2 in that an engine 202 to be
mounted on a snowmobile 201 is set inclined forwards in an engine
compartment 206 so as to reduce the full height of engine 202 while
the aforementioned components are laid out in the space created by
the inclined arrangement of the engine.
[0009] On the other hand, in order to enhance the power of a
four-cycle engine which is relatively low in power compared to a
two-cycle engine, it is generally known that a supercharger
(so-called turbocharger) is provided on the intake side of the
engine so as to increase the amounts of air and fuel to be supplied
to the combustion chamber, to thereby enhance the engine power.
[0010] When the engine has a supercharger, provision of an
intercooler in the intake line is effective in improving the intake
efficiency. However, the position at which the intercooler is
attached needs careful thought as to the cooling efficiency of the
engine and is affected by the attached position of the
supercharger, so that it has been very difficult to design the
layout and allot mounting spaces for these components in the engine
compartment.
[0011] For example, when the intercooler is arranged on the top of
the engine, the full height of the engine becomes high so that the
center of gravity as well as the body height of the snowmobile
becomes high, hence the result is not preferable.
[0012] On the other hand, when the intercooler is arranged in front
of the engine, the heavy part is located away from the center of
gravity, so that the maneuverability lowers. Further, there is
another drawback in that if the snowmobile is collided, the front
part of the engine compartment will crush so that damage to the
engine will become serious.
[0013] For a four-cycle engine, the oil pan, designated at 238,
needs to be positioned at the engine bottom. If the engine is of a
wet sump type, a large oil pan 238 is needed, which will cause
difficulty of interference with the steering shaft designated at
224, as shown in FIG. 2.
[0014] Further, for a snowmobile, the underside of the engine
compartment serves as a sled sliding over snow, hence needs to be
closed, which makes maintenance work such as changing oil
difficult.
[0015] Moreover, when a four-cycle engine with a V-belt type
automatic transmission is used for a snowmobile, the engine is used
at higher speeds compared to that of a four-wheel vehicle.
Therefore, the engine oil increases in temperature due to increased
amount of heat from the engine, whereby oil film starvation may
occur, leading to damage to the engine.
SUMMARY OF THE INVENTION
[0016] The present invention has been devised in view of the above
conventional difficulties, it is therefore an object of the present
invention to provide a snowmobile four-cycle engine arrangement
with which space saving in the engine compartment is achieved and
the workability of maintenance is improved. It is another object of
the present invention to provide a snowmobile four-cycle engine
arrangement with which cooling performance of the air and engine
oil supplied to the engine is improved and space saving is achieved
without any loss of maneuverability.
[0017] In order to achieve the above object, the present invention
is configured as follows:
[0018] In accordance with the first aspect of the present
invention, a snowmobile four-cycle engine arrangement includes: a
four-cycle engine arranged in an engine compartment formed in the
front body of a snowmobile with its crankshaft laid substantially
parallel to the body width and having a cylinder portion inclined
forwards with respect to the vehicle's direction of travel, the
engine employing a dry sump oil supplying system; and an oil tank
provided in the engine compartment, separately from the engine.
[0019] In accordance with the second aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above first feature is characterized in that the oil tank is
arranged in front of the engine and on the top of a front
suspension housing which is projected upwards from the bottom of
the engine compartment.
[0020] In accordance with the third aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above first feature is characterized in that the oil tank is
arranged in the rear of the engine and on the upper face of a track
housing which is projected upwards from the bottom of the engine
compartment.
[0021] In accordance with the fourth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above second feature is characterized in that the oil tank is
arranged in the rear of the engine and on the upper face of a track
housing which is projected upwards from the bottom of the engine
compartment.
[0022] In accordance with the fifth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above first feature is characterized in that the engine compartment
has an opening port with a mating openable and closable lid
element, at its bottom for creating communication between the
inside of the engine compartment and the external space, at a
position opposing the bottom of the oil pan of the engine.
[0023] In accordance with the sixth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above second feature is characterized in that the engine
compartment has an opening port with a mating openable and closable
lid element, at its bottom for creating communication between the
inside of the engine compartment and the external space, at a
position opposing the bottom of the oil pan of the engine.
[0024] In accordance with the seventh aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above third feature is characterized in that the engine compartment
has an opening port with a mating openable and closable lid
element, at its bottom for creating communication between the
inside of the engine compartment and the external space, at a
position opposing the bottom of the oil pan of the engine.
[0025] In accordance with the eighth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above fourth feature is characterized in that the engine
compartment has an opening port with a mating openable and closable
lid element, at its bottom for creating communication between the
inside of the engine compartment and the external space, at a
position opposing the bottom of the oil pan of the engine.
[0026] In accordance with the ninth aspect of the present
invention, a snowmobile four-cycle engine arrangement includes: a
four-cycle engine having a cylinder head on the top thereof and
arranged in an engine compartment formed in the front body of a
snowmobile with its crankshaft laid substantially parallel to the
body width and its engine body inclined forwards with respect to
the vehicle's direction of travel; and an intake path on the upper
face of the engine body, and is characterized in that a heat
exchanger for cooling the engine cooling water, engine oil or air
to be supplied to the engine is arranged in the tunnel created
inside the body frame for accommodating a track for driving.
[0027] In accordance with the tenth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above ninth feature is characterized in that the heat exchanger is
disposed in front of the track, with respect to the vehicle's
direction of travel, inside the tunnel.
[0028] In accordance with the eleventh aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above ninth feature is characterized in that an intercooler for
cooling the air to be supplied to the engine is put into use as the
heat exchanger.
[0029] In accordance with the twelfth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above tenth feature is characterized in that an intercooler for
cooling the air to be supplied to the engine is put into use as the
heat exchanger.
[0030] In accordance with the thirteenth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above ninth feature is characterized in that an oil cooler for
cooling the engine oil is put into use as the heat exchanger.
[0031] In accordance with the fourteenth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above tenth feature is characterized in that an oil cooler for
cooling the engine oil is put into use as the heat exchanger.
[0032] In accordance with the fifteenth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above ninth feature is characterized in that a radiator for cooling
the engine cooling water is put into use as the heat exchanger.
[0033] In accordance with the sixteenth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above tenth feature is characterized in that a radiator for cooling
the engine cooling water is put into use as the heat exchanger.
[0034] In accordance with the seventeenth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above ninth feature is characterized in that an integrated
configuration comprised of an oil cooler for cooling the engine oil
and a radiator for cooling the engine cooling water is put into use
as the heat exchanger.
[0035] In accordance with the eighteenth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above tenth feature is characterized in that an integrated
configuration comprised of an oil cooler for cooling the engine oil
and a radiator for cooling the engine cooling water is put into use
as the heat exchanger.
[0036] In accordance with the nineteenth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above thirteenth feature is characterized in that a thermostat is
interposed in the oil path of the oil cooler.
[0037] In accordance with the twentieth aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above fourteenth feature is characterized in that a thermostat is
interposed in the oil path of the oil cooler.
[0038] In accordance with the twenty-first aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above seventeenth feature is characterized in that a thermostat is
interposed in the oil path of the oil cooler.
[0039] In accordance with the twenty-second aspect of the present
invention, the snowmobile four-cycle engine arrangement having the
above eighteenth feature is characterized in that a thermostat is
interposed in the oil path of the oil cooler.
[0040] According to the present invention, since the engine employs
a dry sump oil supplying system, it is possible to make the engine
body low in height. Since the oil tank is provided in the engine
compartment, separately from the engine, it is possible to make
efficient use of the space inside the engine compartment as well as
to provide a compact engine arrangement.
[0041] Since the oil tank is arranged in front of the engine, on
the upper surface of the front suspension housing, it is possible
to attain space saving. Further, this arrangement allows the oil
tank to receive little thermal influence from the engine and makes
it possible to cool the engine oil effectively from the air flow
during running.
[0042] Further, since the oil tank is arranged on the top face of
the track housing in the rear of the engine, it is possible to
achieve space saving as well as to dispose it apart from the heat
source of the engine. Further, the oil tank can be cooled by snow
powder stirred up during running, so that the engine oil can be
cooled efficiently.
[0043] Since the engine compartment has an opening port with an
openable and closable lid element for creating communication
between the inside of the engine compartment and the external
space, it is possible to make an access to the engine from the
underside of the engine compartment when maintenance such as
changing oil is needed, hence improve the workability.
[0044] According to the present invention, since the heat exchanger
for cooling the engine cooling water, engine oil or air to be
supplied to the engine is arranged in the tunnel created inside the
body frame for accommodating a track for driving, it is possible to
provide a snowmobile four-cycle engine arrangement in which the
heat exchanger will not receive any thermal influence from the
engine compartment and can be cooled markedly efficiently by snow
powder stirred up during running. Further, provision of the heat
exchanger outside the engine compartment makes it possible to
reduce the engine height so realize deployment of a four-cycle
engine. Further, this configuration enhances space saving in the
engine compartment and is markedly effective in reducing the body
height so avoid any loss of maneuverability.
[0045] Since the heat exchanger is disposed in front of the track,
with respect to the vehicle's direction of travel, in the tunnel,
it is possible to arrange it close to, and approximately below, the
engine. Therefore, the connections such as pipes, etc., can be
shortened, thus making it possible to simplify the communication
paths so reduce the cost.
[0046] Since the intercooler for cooling the air to be supplied to
the engine is put into use as the heat exchanger, it is possible to
efficiently cool the air which has been compressed and sent from
the supercharger and hence is high in temperature to thereby
improve the engine power.
[0047] Since the oil cooler for cooling the engine oil is put into
use as the heat exchanger, it is possible to efficiently cool the
engine oil which is high in temperature. Therefore, it is possible
to prevent oil film starvation hence prevent damage to the engine
to thereby maintain the engine in a good running state.
[0048] Since the radiator for cooling the engine cooling water is
put into use as the heat exchanger, it is possible to efficiently
cool the cooling water which is high in temperature. Therefore, it
is possible to prevent the engine from overheating so keep the
engine in a good running state.
[0049] Since the oil cooler for cooling the engine oil and the
radiator for cooling the engine cooling water are integrated as the
heat exchanger, it is possible to eliminate the necessity of
providing an oil cooler and radiator separately hence achieve space
saving and reduce the number of parts.
[0050] Since a thermostat is interposed in the oil path of the oil
cooler, the engine oil can be kept at a proper temperature.
Therefore, it is possible to prevent the engine oil from being
excessively cooled, hence keep the engine in a good running
state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0051] FIG. 1 is a partially sectional side view showing an overall
configuration of a snowmobile having a conventional four-cycle
engine mounted thereon;
[0052] FIG. 2 is an illustrative view showing an overall
configuration of a conventional snowmobile four-cycle engine;
[0053] FIG. 3 is a partially sectional side view showing an overall
configuration of a snowmobile employing a snowmobile four-cycle
engine arrangement in accordance with the embodiment of the present
invention;
[0054] FIG. 4 is a partially sectional plan view showing an overall
configuration of a snowmobile of a first variational example of the
present embodiment;
[0055] FIG. 5 is a sectional side view showing the bottom
arrangement of an engine compartment of a second variational
example of the present embodiment;
[0056] FIG. 6 is a bottom view showing the bottom arrangement of
the engine compartment;
[0057] FIG. 7 is a sectional side view showing the bottom
arrangement of an engine compartment of a third variational example
of the present embodiment;
[0058] FIG. 8 is a bottom view showing the bottom arrangement of
the engine compartment;
[0059] FIG. 9 is a partially sectional side view showing an overall
configuration of a snowmobile four-cycle engine in accordance with
the second embodiment of the present invention;
[0060] FIG. 10 is a partially sectional plan view showing an
overall configuration of a snowmobile four-cycle engine of the
second embodiment;
[0061] FIG. 11 is a partially sectional side view showing an
overall configuration of a snowmobile four-cycle engine of the
third embodiment; and
[0062] FIG. 12 is a partially sectional plan view showing an
overall configuration of a snowmobile four-cycle engine of the
third embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0063] The embodiment of the present invention will hereinafter be
described in detail with reference to the accompanying
drawings.
[0064] FIG. 3 is a partially sectional side view showing an overall
configuration of a snowmobile employing a snowmobile four-cycle
engine arrangement in accordance with the embodiment of the present
invention.
[0065] A snowmobile four-cycle engine according to this embodiment
is arranged as shown in FIG. 3. That is, a four cycle engine 2
having a cylinder head 3 at the top thereof is arranged in an
engine compartment 6 enclosed by a front cover 4 on the front body
side of a snowmobile 1 and is inclined forwards with respect to the
vehicle's direction of travel with its crankshaft (not shown) laid
substantially parallel to the body width and an intake path 5 on
the top thereof.
[0066] Engine 2 employs a dry sump oil supplying system
therein.
[0067] Now, the configuration of snowmobile 1 will be explained in
detail.
[0068] Snowmobile 1 has a body frame 10 extending front to rear as
shown in FIGS. 3 and 4 with a pair of steerable, ski-type runners
13 arranged on the left and right under the front frame, designated
at 11, so as to be turned to the left and right. Arranged under the
rear frame, designated at 12, is a tractive crawler 16 including a
circulating continuous track belt 15. This crawler 16 comprises a
drive wheel 17 arranged at the front end of rear frame 12, an idle
wheel 18 arranged at the rear end and a multiple number of middle
wheels 19, a suspension mechanism 20 and the track belt 15 wound
around these wheels and driven circulatively.
[0069] Body frame 10 has a monocoque frame configuration. The front
frame (engine mount frame) 11 on which engine 2 is mounted is
comprised of a main part 11a as a middle part, a front suspension
housing 11b projectively formed upward in front of the main part
for accommodating the upper part of front suspension 13a for
supporting steerable ski-type runners 13, and a track housing 11c
raised upwards and rearwards from the main part 11a for
accommodating the upper part of drive wheel 17 of crawler 16. This
track housing 11c is continuously and integrally formed with rear
frame 12.
[0070] The rear frame 12 is extended to the rear with respect to
the vehicle's direction of travel and also functions as the cover
for accommodating the whole crawler 16 under it.
[0071] A saddle type seat 22 is arranged on the top of rear frame
12 with steps 23 disposed below on both sides of seat 22.
[0072] A steering shaft 24 is provided extending upward
substantially in the center of the body between seat 22 and front
cover 4 while handlebars 26 extending horizontal to the left and
right and inclined rearwards are attached at the top of steering
shaft 24.
[0073] Disposed upright in front of handlebars 26 is a windshield
28, from the base of which front cover 4 is formed in a
substantially streamline shape, or in a substantially hull-bottom
shape gradually lowering to the front.
[0074] Steerable ski-like runners 13 are adapted to be steered via
steering shaft 24 by handlebars 26.
[0075] Next, the configuration of engine 2 will be described in
detail.
[0076] As shown in FIG. 3, engine 2 is a four-cycle engine and is
arranged at the approximate center of engine compartment 6 inside
front cover 4 with its crankshaft (not shown) laid substantially
parallel to the body width and its cylinder head 3 inclined at a
large angle forwards in the vehicle's direction of travel.
[0077] An intake path 5 including a carburetor and throttle body is
arranged on the upper side of the engine 2 body, an alternator 31
and air cleaner 32 being arranged to the rear, downstream of the
intake path.
[0078] A flywheel (not shown) is disposed at one end (on the left
side with respect to the vehicle's direction of travel) of the
crankshaft and a V-belt type stepless transmission (not shown)
incorporating a centrifugal clutch is arranged on the outer side of
this flywheel. This stepless transmission is configured so as to
transmit drive power to track belt 15 via gears etc., on the
receiving side. A brake (not shown) is fitted at the other end of
the receiving shaft of the stepless transmission.
[0079] Arranged at the other end of the crankshaft (on the right
side with respect to the vehicle's direction of travel) is a pulley
34 functioning as a transmission for driving auxiliary equipment so
as to drive alternator 31 and a water pump 35.
[0080] A starter motor (not shown) is arranged in proximity to the
flywheel on the top of the engine 2 body and under intake path 5
such as carburetor, throttle body etc. Disposed on the top of the
engine 2 body is an intake manifold 37 which branches the intake
path 5 from carburetor 36 into the intake ports of the individual
cylinders. The intake system of carburetor 36 and air cleaner 32
from intake manifold 37 is coupled and arranged above the top
position of cylinder head 3 and extended to the rear.
[0081] This intake system is located under front cover 4 behind the
base of windshield 28 from where it extends upward. The top part of
cylinder head 3 is accommodated, without interference with other
components, in the front inner side of front cover 4 where it
gradually lowers toward the front.
[0082] As the exhaust system, an unillustrated exhaust manifold is
extended from the cylinder case, designated at 39, to the front of
engine 2 and is connected to a supercharger 7. An exhaust path is
created rearwards along the engine 2 body from this supercharger 7
located at the engine 2 front. That is, supercharger 7 is connected
by way of the exhaust path to an unillustrated muffler arranged on
one side in the rear of the engine.
[0083] As shown in FIG. 3, engine 2 is inclined forwards in engine
compartment 6 and mounted on, and along, front frame 11 with an oil
pan 38 arranged adjacent to inclined track housing 11c and cylinder
case 39 arranged adjacent to front suspension housing 11b. An oil
tank 40 is arranged on the top of front suspension housing 11b in
front of and separately from, engine 2.
[0084] The engine oil distributed to parts of the engine returns
into oil pan 38 and goes to the oil tank 40 via an oil strainer 41
and is re-supplied appropriately to the parts of the engine.
[0085] In main part 11a constituting part of engine compartment
bottom 6a, an opening port 50 for maintenance which establishes
communication between engine compartment 6 and the external space
and a lid element 51 for opening and closing the opening port 50
are provided at a position opposing the bottom of oil pan 38 of
engine 2.
[0086] This opening port 50 is approximately rectangular-shaped and
has a size which allows for maintenance of oil pan 38 from the
underside of engine compartment 6.
[0087] The one side of lid element 51 is engaged at one side of
opening port 50 with a connecting means 52 such as a hinge etc., so
that the lid element will be able to pivotally open. A lock
mechanism 53 is provided on the other side of lid element 51 so
that lid element 51 can be positively fixed to engine compartment
bottom 6a when opening 50 is closed.
[0088] Thus, according to this embodiment, since engine 2 of a dry
sump type is arranged inclined forwards with the oil pan 38 at the
bottom of engine 2 close to main part 11a, it becomes possible to
arrange engine 2 in engine compartment 6 in a compact manner.
[0089] Since oil tank 40 is arranged in front of cylinder head 3 of
engine 2, on the upper surface of front suspension housing 11b,
which is projected into engine compartment 6, it is possible to
provide a space saving engine arrangement by making the best use of
the front space of engine 2. Further, this arrangement allows the
oil tank to receive little thermal influence from the engine and
makes it possible to cool the engine oil effectively from the air
flow during travel.
[0090] Further, since opening port 50 for maintenance is formed at
a position opposing oil pan 38 of engine compartment 6a so as to
allow maintenance work such as changing oil etc., to be performed
outside engine compartment 6, the maintenance performance can be
markedly improved.
[0091] Provision of opening port 50 in an openable and closable
configuration has the advantage of not affecting the travel
performance of the snowmobile.
[0092] Though in the present embodiment engine 2 is arranged
inclined forwards inside engine compartment 6, the present
invention should not be limited to this. For example, as a first
variational example, an engine 102 may be mounted substantially
upright in engine compartment 6 as shown information FIG. 4 with an
oil tank 141 arranged on the top surface of front suspension
housing 11b located in front of the engine. It is understood that
this arrangement is a simple extension of the present
invention.
[0093] Further, in the present embodiment, oil tank 40 is arranged
on the top surface of front suspension housing 11b in front of
engine 2. However, the present invention should not be limited to
this. For example, an oil tank 140 may be arranged on the top face
of track housing 11c behind engine 2 as is indicated by a broken
line in FIGS. 3 and 4. In this case, it is possible to provide a
space saving arrangement by making effective use of the space over
track housing 11c behind engine 2. Further, since the oil tank is
located apart from the heat source of the engine and can be cooled
by snow powder stirred up during running, the engine oil can be
cooled efficiently.
[0094] Though, in this embodiment, hinged lid element 51 is
provided so as to open and close the opening port 50 formed at
engine compartment bottom 6a, the present invention should not be
limited to this. For example, as a second variational example, a
lid element 151 having an approximately congruent shape with an
opening port 150 formed at the engine compartment bottom 6a can be
provided separately. That is, the lid element may be fitted to the
opening port 150 and integrally fixed to engine compartment bottom
6a with fasteners 152 such as fastening bolts or the like. In the
drawing, reference numeral 153 denotes a threaded hole to secure
screw fastener 152.
[0095] In this case, opening port 150 may be depressedly formed
into the engine compartment 6 by a height approximately equal to
the thickness of lid element 151. This makes it possible to arrange
the lid element 151 substantially flush with the engine compartment
bottom 6a, providing a refined appearance as well as reducing air
drag during travel.
[0096] As a third variational example, as shown in FIGS. 7 and 8,
an opening port 250 with its inner periphery formed with a thread
250a may be formed on engine compartment bottom 6a so as to be
projected into engine compartment 6 while a lid element 251 with a
thread 251a, mating the thread 250a, formed on its outer periphery
may be provided separately. In this case, since no other fastener
is needed when lid element 251 is attached to opening port 250, it
is possible to improve work performance as well as to use fewer
components so reduce the cost.
[0097] Next, the second embodiment of the present invention will be
described in detail with reference to the drawings.
[0098] FIG. 9 is a partially sectional side view showing an overall
configuration of a snowmobile four-cycle engine in accordance with
the second embodiment of the present invention. FIG. 10 is a
partially sectional plan view showing an overall configuration of
the same snowmobile four-cycle engine.
[0099] A snowmobile four-cycle engine according to the second
embodiment is arranged as shown in FIGS. 9 and 10. That is, similar
to the above first embodiment a four-cycle engine 2 (to be referred
to hereinbelow as engine) having a cylinder head 3 at the top
thereof is arranged in an engine compartment 6 enclosed by a front
cover 4 on the front body side of a snowmobile 1 and inclined
forwards with respect to the vehicle direction of travel with its
crankshaft (not shown) laid substantially parallel to the body
width and an intake path 5 on the top of the inclined engine 2
body. A supercharger (turbocharger) 7 is arranged separately from
the engine 2 body while an intercooler 8 for cooling intake air
sent from this supercharger 7 to the engine 2 body is arranged at
the front side, with respect to the vehicle's direction of travel,
inside the tunnel that is formed on the inner side of a body frame
10 in which an after mentioned drive track belt 15 is
accommodated.
[0100] Here, the configuration of snowmobile 1 is generally the
same as that of the first embodiment except in that the rear frame,
designated at 12, has a tunnel-like configuration from the body
front to the rear, i.e., with the inner side depressed upwards from
the bottom, so as to function as a cover accommodating the whole
track belt 15 under it.
[0101] Next, the configuration of engine 2 will be described in
detail.
[0102] As shown in FIGS. 9 and 10, engine 2 is a four-cycle
three-cylinder engine having its cylinder head 3 on top and is
arranged at the approximate center of engine compartment 6 inside
front cover 4 with its crankshaft (not shown) laid substantially
parallel to the body width and its cylinder head 3 inclined at a
large angle (e.g., more than 45 degrees forwards) in the vehicle's
direction of travel. Other arrangement is the same as in the first
embodiment.
[0103] Next, the intake system will be described.
[0104] In the arrangement of the intake system, the parts to be
disposed on the upper side of engine 2 are positioned under front
cover 4 behind the base of windshield 28 from where it extends
upward while the parts to be disposed in front of cylinder head 3
are accommodated, so as not to interfere with other components, on
the front inner side of front cover 4 where it gradually lowers
toward the front.
[0105] Disposed on the top of engine 2 is an intake manifold 37
which branches the intake path 5 from carburetor 36 into the intake
ports of the individual cylinders.
[0106] A supercharger 7 is arranged in front the engine 2 and an
air cleaner 32 is disposed at the frontmost space in engine
compartment 6.
[0107] An intercooler 8 is arranged in proximity to engine 2 at its
rear bottom, but outside engine compartment 6 and on the inner side
of body frame 10.
[0108] One end of supercharger 7 is connected to an intake passage
7a extended forwards so that the supercharger is connected to air
cleaner 32 via this intake air passage 7a.
[0109] The other end of supercharger 7 is connected to intercooler
8 via an intake air passage 7b which starts from the front side of
engine 2 and is bent along the side face of engine 2, in an L-shape
as viewed from the top, extended to the rear and bent downwards, in
a sectional view, near the engine crankshaft.
[0110] An intake air passage 8a is connected to the outlet side of
the intercooler 8. This intake air passage 8a extends upwards
approximately vertically from the engine 2 bottom and is connected
to carburetor 36 arranged over the engine 2.
[0111] For air supply to engine 2, air is introduced from the body
front via air cleaner 32 into supercharger 7, where the air is
compressed and sent to intercooler 8. In the intercooler 8, the air
which has become high in temperature through supercharger 7 is
cooled and sent to carburetor 36, from where air is supplied to
individual cylinders in engine 2 via intake manifold 37.
[0112] On the other hand, the exhaust path starts from cylinder
case 39 toward the front side of engine 2 and is connected to the
inlet side of supercharger 7 via an exhaust manifold 41. The outlet
side of supercharger 7 is connected to an exhaust passage 42, which
is extended from the front side of the engine 2 body to the rear
along the engine 2 body and connected to a muffler 43 arranged at
one side behind the engine.
[0113] Next, mounting of engine 2 will be described.
[0114] As shown in FIG. 9, engine 2 is inclined forwards in engine
compartment 6 and mounted on, and along, front frame 11 with an oil
pan 38 arranged adjacent to inclined track housing 11c and cylinder
case 39 arranged adjacent to suspension housing 11b.
[0115] The engine 2 is attached to track housing 11c by a pair of
oil-pan side brackets 45 on the rear side and to suspension housing
11b by a pair of cylinder-case side brackets 46 on the front side.
Both the oil-pan side brackets 45 and cylinder-case side brackets
46 are angled fittings and arranged left and right. Shock absorbers
47 such as cushion rubber are interposed at the fastening sites to
front frame 11 so that the engine is supported floatingly on front
frame 11.
[0116] According to the second embodiment as above, since intake
path 5 is arranged on the upper side of engine 2, supercharger 7
and air cleaner 32 are disposed in front of the engine in engine
compartment 6 while intercooler 8 is placed outside engine
compartment 6 and inside body frame 10, it is possible to realize a
compact engine layout and markedly improve the cooling performance
of intercooler 8 by eliminating any thermal effect from engine 2
and cooling it by snow powder stirred up during running, to thereby
enhance the charging efficiency of intake air.
[0117] By arranging the intake path and exhaust path from the front
side toward the rear of engine 2 along its body side, it is
possible to improve the cooling effect on the intake and exhaust
path by air flow during travel.
[0118] Next, the third embodiment will be described in detail with
reference to the drawings.
[0119] FIG. 11 is a partially sectional side view showing an
overall configuration of a snowmobile four-cycle engine of the
third embodiment. FIG. 12 is a partially sectional side view
showing an overall configuration of the snowmobile four-cycle
engine. Here, the parts corresponding to those in the second
embodiment are allotted with the same reference numerals without
description.
[0120] A snowmobile four-cycle engine according to the third
embodiment is arranged as shown in FIGS. 11 and 12. That is, a
four-cycle engine 102 (to be referred to hereinbelow as engine)
having a cylinder head 3 at the top thereof is arranged in an
engine compartment 6 enclosed by a front cover 4 on the front body
side of a snowmobile 100 and inclined forwards with respect to the
vehicle's direction of travel with its crankshaft (not shown) laid
substantially parallel to the body width and an intake path 5 on
the top of the inclined engine 2 body.
[0121] An oil cooler 108 is arranged at the front side, with
respect to the vehicle's direction of travel, in the tunnel that is
formed on the inner side of a body frame 10. This oil cooler 108
has a thermostat valve (not shown) between its inlet and outlet oil
paths.
[0122] An intake path 5 including a carburetor and throttle body is
arranged on the upper side of the engine 102 body, an alternator 31
and air cleaner 132 being arranged to the rear, downstream of the
intake path.
[0123] According to the third embodiment as above, since intake
path 5 and air cleaner 132 are arranged on the upper side of engine
102, oil cooler 108 is placed outside engine compartment 6 and in
the front inner side of body frame 10, it is possible to realize a
compact engine layout. Further, since oil cooler 108 is arranged at
the front side, with respect to the vehicle's direction of travel,
in the tunnel that is formed on the inner side of body frame 10 so
that it will not receive any thermal influence from engine 102, it
is possible to efficiently cool the engine oil which is high in
temperature by snow powder stirred up during travel. Therefore, it
is possible to prevent oil film starvation hence prevent damage to
the engine to thereby maintain the engine in a good running
state.
[0124] Further, since a thermostat is interposed in the oil path of
the oil cooler 108, it is possible to prevent the engine oil from
being excessively cooled so keep the engine in a good running
state.
[0125] In the above embodiments, intercooler 8 or oil cooler 108 is
put into use as a heat exchanger and arranged inside the
tunnel-like hollow inside body frame 10. However, the present
invention should not be limited to this arrangement. For example,
the radiator may be arranged inside body frame 10. In this case,
the engine cooling water can be efficiently cooled so that the
engine can be prevented from overheating, thus making it possible
to keep the engine in a good running state.
[0126] Further, in the present invention, the oil cooler for
cooling the engine oil and the radiator for cooling the engine
cooling water may be configured integrally and is put into use as
the heat exchanger. In this case, it is possible to provide a space
saving arrangement and reduce the number of parts because of being
needless of providing an oil cooler and radiator separately.
[0127] As has been described heretofore, according to the
snowmobile four-cycle engine arrangement of the present invention,
since the oil tank is arranged in the engine compartment,
separately from the engine, it is possible to make the use of a
four-cycle engine feasible as well as realizing space saving by
making efficient use of the space inside the engine
compartment.
[0128] Further, since an openable/closable maintenance opening is
provided at the bottom of the engine compartment, this arrangement
is markedly effective in improving the workability of maintenance
when changing oil and the like.
[0129] Since a heat exchanger for cooling the engine cooling water,
engine oil or air to be supplied to the engine is disposed inside
the tunnel that is formed inside the body frame, instead of
arranging it inside the engine compartment, it is possible to
achieve space saving inside the engine compartment and reduce the
engine height, whereby it is possible to realize deployment of a
four-cycle engine, which is environment-conscious.
[0130] Finally, according to the present invention, it is possible
to provide a snowmobile four-cycle engine which is markedly
improved in its cooling performance by snow powder stirred up
during running.
* * * * *